Introduction To The Microsoft .net Framework

Introduction to the Microsoft .NET Framework Chris Wastchak Student Ambassador to Microsoft

What is the .NET Framework • A new computing platform designed to simplify application development • A consistent object-oriented programming environment • A code-execution environment that: – Minimizes software deployment and versioning conflicts – Eliminates the performance problems of scripted or interpreted environments

Primary Components of .NET • .NET Framework Class Libraries – Object-oriented collection of reusable types – Sits on-top of the Common Language Runtime

• Common Language Runtime (CLR) – Manages code execution at runtime – Memory management, thread management, etc. – Code designed for the CLR is referred to as “Managed Code”

Managed execution in the Common Language Runtime (CLR)

Managed Code Common Language Runtime (CLR) Requests for existing features, such as opening a file, mediated by CLR

Win32 OS

New CLR-only features, such as garbage collection

Inside the .NET Framework VB

C++

C#

Web Services

J#

Python

…

User Interface

ASP.NET Data and XML Base Framework

ASP.NET High-productivity environment for building and running Web services

Common Language Runtime (CLR)

Secure, integrated class libraries

Operating System

•Unifies programming models across languages

Common Language Runtime Executes code, maintains security, handles component “plumbing” and dependencies

•Enables cross-language integration •Factored for extensibility •Designed for tools

One Runtime For Many Languages • • • •

CLR is an open standard Any language can make use of CLR services Any language can use classes written in any other language Any language can inherit classes written in any other language

Current List of Language Compilers           

Ada APL Basic (Visual Basic) C# C C++ Java Language COBOL Component Pascal



(Queensland Univ of Tech)



ECMAScript (JScript) Eiffel (Monash



Haskell



(MS Research Redmond)  

(Utrecht University)

Mondrian (Utrecht) ML

(MS Research Cambridge) 

Mercury

(Melbourne U.) 

Oberon

(Zurich University) 



University) 

lcc

Oz (Univ of Saarlandes) SmallTalk Python Scheme (Northwestern U.) Perl

.NET Framework Class Libraries • Sit on top of the CLR • Reusable types that tightly integrate with the CLR • Object oriented – inheritance, polymorphism, etc. • Provide functionality for ASP.NET, XML Web Services, ADO.NET, Windows Forms, basic system functionality (IO, XML, etc.)

The Common Language Runtime • Code that targets the CLR is referred to as managed code • All managed code has the features of the CLR – – – –

Object Oriented Cross-language integration Cross language exception handling Multiple version support (no more DLL Hell)

The Common Language Runtime • The CLR manages object layout and references to objects • Objects whose lifetimes are managed by the CLR are referred to as Managed Data • Automatic memory management reduces memory leaks • In managed code you can use: – Managed Data – Unmanaged data – Both

The Common Language Runtime • All CLR-compliant compilers use a common type system – Allows for cross-language inheritance – Passing object instances across language barriers – Invoking methods across language barriers

• Managed components expose metadata • Metadata includes – Resources component was compiled against – Information about types and dependencies (no more RegServ32)

Managed Execution Process public void Fill() { DotNetJunkies.StudyGroupPortal.Data.EventDB eDB = new DotNetJunkies.StudyGroupPortal.Data.EventDB(); //Create a data reader IDataReader reader = eDB.GetEventByGuid(_guid); //Advance to the first record in the reader reader.Read(); //Populate this instance of the Event class this.CreateEvent(ref reader); //Close the reader reader.Close(); }

Language Specific Compiler

MSIL

Microsoft Intermediate Language • Managed code is compiled to MSIL • CPU-independent set of instructions – Loading, storing, initializing and calling methods – Arithmetic and logical operations, etc. – Control flow, exception handling, direct memory access

Just-In-Time Compiling • Assemblies are compiled to native code by a Just-In-Time compiler (JITer) • Compiled assemblies include metadata • No Type Libraries or Interface Definition Language (IDL)

Compilation And Execution Compilation Source Code

Language Compiler

Native Code

JIT Compiler Execution

Code (IL)

Assembly Metadata

Before installation or the first time each method is called

Just-In-Time Compiling • All assemblies must be compiled to native code before executing • JIT compilers are built into the CLR for every supported CPU architecture • JIT compilers convert MSIL to native on demand • Resulting native code is stored for reuse • JIT compiling occurs for each method after the application is restarted

Summary • .NET Framework is a code execution platform • .NET Framework consists of two primary parts: .NET Class Libraries, Common Language Runtime • All CLR-compliant compilers support the common type system • Managed code is object oriented • Managed code is compiled to an assembly (MSIL) by language specific compiler • Assemblies are compiled to native code by JIT compiler

Questions?